Semi Conductors Objectives Part 08
141 . Thermionic emission of electrons is due to high temperature.
142 . N-P-N transistor electrons will be the majority carriers.
143 . Germanium with Indium doping will produce P-type semi-conductor.
144 . The difference between a hole and electron is that a hole is always in the valance band.
145 . When an electron rises through a potential of 100 V. it will acquire an energy of 100eV.
146 . Hall’s effect can be used to measure magnetic field intensity.
147 . CdS photo conductor is commonly used.
148 . The photo electric threshold of tungsten is 2300 A. The energy of the electrons ejected from the surface by ultra-violet light of wave length 1800 A, will be 1.5eV.
149 . A solar cell is an example of photo voltaic cell.
150 . Barrier potential for silicon diode is 0.7V.
151 . When light is directed at the metal surface, the emitted electrons have energies that depend on frequency of lights.
152 . A strong electric field across a P-N junction that causes covalent bonds to break apart it is called lever break down.
153 . An ideal diode should have zero resistance in forward bias and an infinity large resistance in reverse bias.
154 . The bulk resistance of a diode is the resistance of the P and N material only.
155 . Electrons only can exist outside of a semiconductor material.
156 . In case of semi-conductors, recombination is merging of an outside electron with semiconductor electron.
157 . When a PN-junction is reverse biased holes and electrons moves away from the junction.
158 . In case a PN-junction is forward biased holes and electrons moves towards the junction.
159 . Mobile electrons of P-side of the PN-junction diode constitute minority current carriers.
160 . When a PN-junction is reverse biased a very small amount of reverse current called leakage current flows.